Touch screen devices are mainstream electronic products in the prior art, having a rich variety of unlocking methods, which may basically utilize a way of slide-to-unlock, such as sliding from left to right or from right to left in a straight line, or drawing a multi-point connecting line, or lining out an icon from a designated area. All these methods belong within the scope of slide-to-unlock.
Slide-to-unlock has its drawbacks due to the fact that a device may not determine a sliding path correctly, for instance, it may be hard to control the length of a sliding path or the force exerted on the sliding path. There appears to be no technical solution in the prior art using two-point touches to unlock a screen; therefore, there is much room for the prior art to be improved and developed.